1. Field of the Invention
The present invention relates to a display device, and more particularly, to a display device having a plurality of power supplies and a method for controlling the same.
2. Discussion of the Related Art
There are a wide variety of display devices. The television is a typical display device.
The television tunes in to a broadcast signal received through a channel selected by a user, from among broadcast signals transmitted from a broadcast station, and demodulates and separates the tuned broadcast signal into audio and video data.
The television processes the audio and video data so that the audio and video data can be output respectively through a speaker and a screen of the television. The television then outputs the processed audio and video data respectively through the speaker and screen.
The variety of televisions include not only a Cathode Ray Tube (CRT) television, which is the most widely used one, but also televisions that use a Liquid Crystal Display (LCD), a Plasma Display Panel (PDP), and the like for satisfying demand for high image quality and large screen.
Due to its structural characteristics, the PDP television can be made to be much thinner than the general CRT television and also exhibits much higher luminance than the LCD television.
It is also easy to install the PDP television on the wall. Due to such good features, the PDP television is attracting lots of attention as a next generation TV.
However, a high voltage is required to drive PDP display devices due to the characteristics of PDP display devices. Thus, one of the most important technologies in popularizing PDP display devices is a technology for efficiently controlling components associated with the power supply.
A PDP display device generally includes upper and lower substrates that are laminated together. The upper substrate includes scan and sustain electrodes formed in parallel on a substrate and dielectric and protective layers formed over the substrate including the scan and sustain electrodes.
The lower substrate includes address electrodes formed on a substrate, a dielectric layer formed over the substrate including the address electrodes, partition walls formed between the address electrodes and between the dielectric layers, and fluorescent material formed on the surface of the dielectric layer and on the surfaces of partition walls in each discharge cell.
A space between the upper and lower substrates is filled with a discharge gas mixed with an inert gas such as He or Xe, so that the space therebetween forms a discharge area.
In such a PDP display device, specific voltages are applied to the electrodes to cause an electrical discharge in the discharge gas. This produces ultraviolet light, and the fluorescent material is excited by the ultraviolet light, thereby displaying colors.
The PDP display device includes a module driver to drive the PDP module so that the specific voltages are applied to the electrodes at preset times.
FIG. 1 is a block diagram of a conventional display device that has a power supply control apparatus.
With reference to FIG. 1, a description will now be given of how power is supplied in the conventional display device.
The following description will focus particularly on a PDP display device among the conventional display devices.
As shown in FIG. 1, the conventional display device 101 includes a standby power supply 102, a microcomputer 103, a PFC 104, a relay 105, a relay driver 106, a Vs power supply 107, a Va power supply 108, a Vsetup power supply 109, a Vsc power supply 110, and a PDP module 112. The standby power supply 102 supplies standby power to the components of the display device 101 to allow them to respond to an operating command input by a user using a remote controller or the like while the display device is in standby mode, i.e., while no image is displayed. The microcomputer 103 receives drive power from the standby power supply 102 and outputs a control signal according to a preset control algorithm. The PFC 104 receives input commercial AC power and corrects the power factor. The relay 105 controls power supply to the PFC 104. The relay driver 106 controls the operation of the relay 105 according to a control signal from the microcomputer 103. The Vs power supply 107 transforms an output voltage of the PFC 104 to supply Vs power to drive sustain electrodes. The Va power supply 108 transforms the output voltage of the PFC 104 to supply Va power to drive address electrodes. The Vsetup power supply 109 transforms the output voltage of the PFC 104 to supply a setup voltage. The Vsc power supply 110 transforms the output voltage of the PFC 104 to supply Vsc power to drive scan electrodes. The PDP module 112 is driven by the power supplied from the Vs power supply 107, the Va power supply 108, the Vsetup power supply 109, and the Vsc power supply 110.
A more detailed description will now be given of how the conventional display device 101 operates to control the power.
First, once the user inputs a command to power on the display device 101, the microcomputer 103 detects the command and drives the components of the display device 101 according to a preset control algorithm.
For example, the microcomputer 103 outputs a control signal to the relay driver 106 to drive it. As the relay 105 is driven, power is supplied to the PFC 104, whereby power is also supplied to the Vs power supply 107, the Va power supply 108, the Vsetup power supply 109, and the Vsc power supply 110.
Specifically, when the user presses down a button to power on the display device 101, a control signal is first output to the relay driver 106, and a control signal is then output to the Vs power supply 107, the Va power supply 108, the Vsetup power supply 109, and the Vsc power supply 110.
The Vs power supply 107, the Va power supply 108, the Vsetup power supply 109, and the Vsc power supply 110 supply their powers to corresponding electrodes, thereby driving the PDP module 112 so that images of a channel selected by the user are displayed on the screen of the display device 101.
However, the method for controlling the power of the conventional display device 101 (for example, a PDP display device) has the following problems.
First, increasing the screen size of the display device requires that higher power be supplied to the display device, and a new power board dedicated to large modules must be separately manufactured to supply higher power to the conventional display device.
Second, the conventional display device has no way to determine whether the power supply is operating normally or abnormally.